That's super unhealthy and toxic
And you're aware of it ...it's up to you to be done

Move on or get dragged along

There's a thing known to psychologists - romantic attachments that form between 13- and 16-years-old often last for life - whether toxic or not.

So if you're choosing to stay together, your best bet is to discuss the idea of growing out of toxicity and into maturity together.

I can recommend several paths that helped me enormously.
Using all of them simultaneously would help the most.

Vipassana meditation. The 10-day courses are free - you give a donation according to your means at the end. They teach how to develop mindfulness - this is the best way to become more aware of feelings before blurting them out in ways that might hurt one another.

Codependents Anonymous. A free 12-step fellowship which helps participants let go of trying to control others, and learn healthy boundaries and self-responsibility.
Although it advocates coming to believe in a Higher Power of your own understanding, atheists can choose to rely on the group ( the fellowship). There is no restriction on what your Higher Power might be. It could be Unconditional-Loving-Kindness or just Love for short.
It can also provide access to a wealth of relevant self-help books.

Daniel Goleman - book - Emotional Intelligence

Marshall Rosenberg - book - Nonviolent Communication - a simple four-step method for listening, communicating and finding mutually agreeable solutions. It can help to join a free weekly practice group. There are videos of the process which can be watched for free on YouTube. Rosenberg himself is a little hard to look at, and the timbre of his voice is not that pleasant to listen to - but if you can get past that, the content of what he offers is brilliant - pure genius and all heart - a passport to functional relationships of all kinds.

Wishing you all the best. :)

Just try to listen to your heart and pray if your religious

When you’re in love you just don’t see things clearly.

It's not easy to move on. But you will regret not doing it sooner

I can relate a little

Got really close to my best friend and we talked about getting married, and she kept going back to her ex and doing meth with him and having sex with him, but I don't want literally anyone else ever

Consider therapy